Generally, an amino-based organic solvent has desired performance as a solvent or a detergent since it has improved solubility and is capable of being rinsed with water due to its property of being dissolved easily in water. For these reasons, an amino-based organic solvent can be used as a resist peeling agent, for example.
In recent years, there is a tendency that a conventional halogen-based solvent is replaced by an amide-based solvent since a halogen-based solvent may cause environment pollution as it destroys the ozone layer or the like, and also has strong toxicity. In addition, an amide-based solvent is expected to be used instead of a reproductive toxic compound such as NMP.
However, a method for synthesizing an amide-based solvent at a low cost has not yet been established. Under such circumstances, an inexpensive method for synthesizing an amide-based solvent which can be realized on the industrial scale has been awaited.
As the method for synthesizing an amide-based solvent at a low cost, a method in which an acrylic acid ester is used as a starting material can be given. Specifically, the following methods can be used. An alkoxypropionic acid ester is synthesized from an acrylic acid ester, and the resulting alkoxypropionic acid ester is directly amidized, or, an alkoxypropionic acid ester is once hydrolyzed to produce an alkoxyacrylic acid, and the resulting alkoxyacrylic acid is reacted with an amine to form a salt, followed by heat decomposition to allow an amide to be synthesized.
For example, Patent Document 1 discloses synthesis of β-alkoxy-N,N-dialkylpropionamide as an intermediate in a method for producing a N,N-dialkylpropionamide of an α,β-olefin-based unsaturated monocarboxylic acid which is used as a polymerizable monomer. Specifically, this is a method in which a β-alkoxypropionic acid ester and a dialkylamine are reacted in the presence of a polyol having two adjacent hydroxyl groups.
This method, however, requires a large amount of a polyol. In addition, in order to attain a high conversion ratio, it is necessary to conduct a reaction for a long period of time at high temperatures.
Patent Document 2 discloses a method in which an acrylic acid amide is reacted with an aliphatic monovalent alcohol having 1 to 4 carbon atoms. According to this method, synthesis can be performed under moderate conditions.
However, an acrylic acid amide is generally produced in three to four steps, as stated in Patent Document 2. In addition, an acrylic acid amide itself is expensive. Therefore, production cost is increased if a β-alkoxypropionamide is produced by this method.
In addition, a method is known in which dimethylamine is reacted with alkoxy acid chloride. For example, by reacting dimethylamine with 3-ethoxy-propionylchloride in the presence of a diethyl ether solvent, 3-ethoxy-N,N-dimethyl-propionamide can be synthesized.
However, this method is not an inexpensive synthesis method, since raw materials are expensive.
Patent Document 1: JP-A-S49-66623
Patent Document 2: JP-A-H10-279545
An object of the invention is to provide a method which is capable of producing a β-alkoxypropionamide, which is effective as an amide-based organic solvent, at a low cost.